their job was to groom the cliff side so that rocks wouldn't fall on the men working below. >> reporter: so they're chicago he willing away. >> they're chicago he willing away, boring holes for dynamite. they're placing dynamite. they're doing all these things and they're doing it basically suspended in midair. some of them got reputations as being real acrobats. people would come to the top of the cliff to watch them perform. >> reporter: the project was finished in 1935 for more than $100 million. equivalent to about a quarter of the country's entire annual public works budget back then. f.d.r. himself showed up to dedicate it. >> on behalf of the nation, we say to you well done. >> reporter: it's its official name was bolder dam. the democrats in power, having stripped republican hoover's name right off it. >> hoover, of course, is out of office. not only was he not invited. it was a full day of ceremony. many many speeches including the keynote speech by the president himself. and herbert hoover's name was not mentioned once. >> reporter: it would take 14 years and a republican cong